A Study of 2 Doses of Menactra®, a Meningococcal Conjugate Vaccine in Healthy Toddlers

Inclusion Criteria: * Healthy, as determined by medical history and physical examination. * Aged 9 months (249 to 291 days) at the time of enrollment. * The parent or legal guardian has signed and dated the Institutional Review Board-approved informed consent form Exclusion Criteria: * Serious acute or chronic disease (e.g., cardiac, renal, metabolic, rheumatologic, psychiatric, hematologic, or autoimmune disorders, diabetes, atopic conditions, congenital defects, convulsions, encephalopathy, blood dyscrasias, leukemia, lymphomas of any type, or other malignant neoplasms affecting the bone marrow or lymphatic system, acute untreated tuberculosis) that could interfere with trial conduct or completion. * Known or suspected impairment of immunologic function. * Acute medical illness within the last 72 hours, or temperature ≥ 100.4 ºF (≥ 38.0 ºC) at the time of enrollment. * History of documented invasive meningococcal disease or previous meningococcal vaccination. * Known human immunodeficiency virus (HIV), hepatitis B, or hepatitis C seropositivity as reported by the parent or legal guardian * Received either immune globulin or other blood products within the last 3 months, or received injected or oral corticosteroids, or other immunomodulator therapy within 6 weeks of the study vaccines. Individuals on a tapering dose schedule of oral steroids lasting \< 7 days and individuals (e.g., asthmatics) on a short schedule of oral steroids lasting 3 to 4 days may be included in the trial as long as they have not received more than one course within the last two weeks prior to enrollment. Topical steroids are not included in this exclusion criterion. * Anticipated to receive oral or injected antibiotic therapy within the 72 hours prior to the study blood draw. Topical antibiotics or antibiotic drops are not included in this exclusion criterion. * Suspected or known hypersensitivity to any of the vaccine components, or history of a life-threatening reaction to the study vaccines or a vaccine containing the same substances. For ProQuad vaccine recipients, this includes a hypersensitivity to gelatin or a history of anaphylactic reactions to neomycin. * Thrombocytopenia or a bleeding disorder contraindicating intramuscular (IM) vaccination. * Parent or legal guardian unable or unwilling to comply with the study procedures. * Participation in another interventional clinical trial in the 30 days preceding enrollment, or participation in another clinical trial involving the investigation of a drug, vaccine, medical procedure, or medical device during the subject's trial period. * Diagnosed with any condition which, in the opinion of the investigator, would pose a health risk to the subject or interfere with the evaluation of the vaccine. * Received any vaccine in the 30-day period prior to receipt of study vaccine, or scheduled to receive any vaccination other than influenza vaccination and hyposensitization therapy in the 30-day period after receipt of any study vaccine. Hyposensitization therapy and influenza vaccination may be received up to two weeks before or two weeks after receiving the study vaccines. Subjects should not have received their 4th dose of Pneumococcal Conjugate (PCV) or Hib vaccine or their first dose of Measles-Mumps-Rubella-Varicella (MMRV) vaccine before enrollment. * Personal or family history of Guillain-Barré Syndrome (GBS). * History of seizures, including febrile seizures, or any other neurologic disorder. * Known hypersensitivity to dry natural rubber latex (pertinent to the Menactra® vaccine needle shield)